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/*
* Copyright (C) 2010 Marek Olšák <maraeo@gmail.com>
*
* All Rights Reserved.
*
* Permission is hereby granted, free of charge, to any person obtaining
* a copy of this software and associated documentation files (the
* "Software"), to deal in the Software without restriction, including
* without limitation the rights to use, copy, modify, merge, publish,
* distribute, sublicense, and/or sell copies of the Software, and to
* permit persons to whom the Software is furnished to do so, subject to
* the following conditions:
*
* The above copyright notice and this permission notice (including the
* next paragraph) shall be included in all copies or substantial
* portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
* IN NO EVENT SHALL THE COPYRIGHT OWNER(S) AND/OR ITS SUPPLIERS BE
* LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
* OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
* WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
*
*/
#include "radeon_remove_constants.h"
void rc_remove_unused_constants(struct radeon_compiler *c,
unsigned **out_remap_table)
{
unsigned char *const_used;
unsigned *remap_table;
unsigned *inv_remap_table;
unsigned has_rel_addr = 0;
unsigned is_identity = 1;
unsigned are_externals_remapped = 0;
struct rc_constant *constants = c->Program.Constants.Constants;
if (!c->Program.Constants.Count) {
*out_remap_table = NULL;
return;
}
const_used = malloc(c->Program.Constants.Count);
memset(const_used, 0, c->Program.Constants.Count);
/* Pass 1: Mark used constants. */
for (struct rc_instruction *inst = c->Program.Instructions.Next;
inst != &c->Program.Instructions; inst = inst->Next) {
const struct rc_opcode_info *opcode = rc_get_opcode_info(inst->U.I.Opcode);
for (unsigned i = 0; i < opcode->NumSrcRegs; i++) {
if (inst->U.I.SrcReg[i].File == RC_FILE_CONSTANT) {
if (inst->U.I.SrcReg[i].RelAddr) {
has_rel_addr = 1;
} else {
const_used[inst->U.I.SrcReg[i].Index] = 1;
}
}
}
}
/* Pass 2: If there is relative addressing, mark all externals as used. */
if (has_rel_addr) {
for (unsigned i = 0; i < c->Program.Constants.Count; i++)
if (constants[i].Type == RC_CONSTANT_EXTERNAL)
const_used[i] = 1;
}
/* Pass 3: Make the remapping table and remap constants.
* This pass removes unused constants simply by overwriting them by other constants. */
remap_table = malloc(c->Program.Constants.Count * sizeof(unsigned));
inv_remap_table = malloc(c->Program.Constants.Count * sizeof(unsigned));
unsigned new_count = 0;
for (unsigned i = 0; i < c->Program.Constants.Count; i++) {
if (const_used[i]) {
remap_table[new_count] = i;
inv_remap_table[i] = new_count;
if (i != new_count) {
if (constants[i].Type == RC_CONSTANT_EXTERNAL)
are_externals_remapped = 1;
constants[new_count] = constants[i];
is_identity = 0;
}
new_count++;
}
}
/* is_identity ==> new_count == old_count
* !is_identity ==> new_count < old_count */
assert( is_identity || new_count < c->Program.Constants.Count);
assert(!(has_rel_addr && are_externals_remapped));
/* Pass 4: Redirect reads of all constants to their new locations. */
if (!is_identity) {
for (struct rc_instruction *inst = c->Program.Instructions.Next;
inst != &c->Program.Instructions; inst = inst->Next) {
const struct rc_opcode_info *opcode = rc_get_opcode_info(inst->U.I.Opcode);
for (unsigned i = 0; i < opcode->NumSrcRegs; i++) {
if (inst->U.I.SrcReg[i].File == RC_FILE_CONSTANT) {
inst->U.I.SrcReg[i].Index = inv_remap_table[inst->U.I.SrcReg[i].Index];
}
}
}
}
/* Set the new constant count. Note that new_count may be less than
* Count even though the remapping function is identity. In that case,
* the constants have been removed at the end of the array. */
c->Program.Constants.Count = new_count;
if (are_externals_remapped) {
*out_remap_table = remap_table;
} else {
*out_remap_table = NULL;
free(remap_table);
}
free(const_used);
free(inv_remap_table);
}
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